Portable power bank



FIG. 1 is a front, left, and bottom view of a portable power bank, showing my new design;

FIG. 2 is a rear, right, and top perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a left side elevation view thereof;

FIG. 8 is a right side elevation view thereof; and,

FIG. 9 is a front, left, and bottom perspective view of the portable power bank of FIG. 1 in a state of use.

The broken lines depict portions of the portable power bank in which the design is embodied that form no part of the claimed design. 

CLAIM The ornamental design for a portable power bank, as shown and described. 